OK, so if it is plugged into a wall, and still won't boot, it is broken. Unplug all power, take out the battery and hold down the power button for 1 minute! You have to unplug the power adapter from the wall, and take it apart until it is two cords. Wait for 1 more minute. Now, put it all back together, and plug it back into the wall. If it still doesn't boot, remove all power, remove the battery and take out the HDD. Try to boot without the drive in it. Did it beep, or did lights flash? If so, then take it to a technician, as there still may be hope for it. If it does NOT beep, or flash lights, then the Motherboard is bad, and there is nothing you could do.